In the food service industry, it is desirable to serve a wide variety of viscous fluids such as sauce, mustard, ketchup, condiments, and the like in hygienic conditions and as conveniently as possible. For that, there are several known types of dispensing devices which utilize both the gravity and the mechanical force to dispense viscous fluids throughout a tube connected to a bag. Such dispensing apparatuses generally do not require any additional pumps.
For example, U.S. Pat. No. 5,833,120 to Evans, Sr. et al. discloses a cheese server being adapted to maintain inverted bags in a steam chamber while gravity influenced squeeze bars ride down the bag sides to express cheese toward the bag outlet fitment. Such an arrangement remains rather complicated and inconvenient when the bag has to be changed by a new one. In particular, the pair of rollers has to be detached from the empty bag, then fitted to a new bag while taking care the rollers are not biased with respect to the bag which would cause blocking problems. In addition, when the bag is loaded with fluid product, it may be difficult to properly engage the pair of rollers through the upper portion of the bag.
U.S. Pat. No. 5,490,613 to Taylor et al. relates to a dispenser for viscous fluid having a hanging assembly for suspending a collapsible bag with a dispenser outlet extending from an opening at the bottom of a housing, and a pair of rollers riding in parallel pairs of slots vertically extending in opposite sides of the housing. In this arrangement, the device also comprises a pair of rollers which can be separated when the housing is opened for engaging a new bag. However, the device is cumbersome as place for the two rollers must be saved accordingly. The rollers have to be joined by an elastic yoke provided on each external side of the housing making the arrangement complicated. Blocking problems are likely to occur, as the two rollers might not ride in a perfect parallel travel all along the length of the bag.
U.S. Pat. No. 5,297,699 to Barchus also relates to an internally-coupled dual roller tube squeezing device for fluid materials such as toothpaste, shampoo, adhesive, or similar.
U.S. Pat. No. 4,639,251 to Kirland relates to a flexible collapsible container containing medical liquids, a pair of rollers being arranged as a level indicator.
U.S. Pat. No. 5,578,001 to Sha is an infusion apparatus for IV bags comprising a squeezing arrangement of two parallel rollers.
None of the devices discussed above provides a satisfactory solution that can be applied as a recognized efficient standard in the food service industry. Accordingly, there remains a need for improved dispensing devices in this area.